Collapsing the echo area

[Whitfield Diffie <the.whitfield.diffie@gmail.com>]

   Can anyone tell me how to get the echo area to return close
without returning to the keyboard.  If I execute

         (progn (message "a\nb\nc\nd\ne\nf\ng\nh\n") (sit-for 1)
                   (message "One-line message") (sit-for 5))

The one line message is exhibited at the top of an eight-line-tall
echo area which peraists until the second sit terminates.  I would
like it to have the one-ine message display in an echo area one line
high.

   (The actual application is to display a count in the echo area
while an ascii art image is displayed in the buffer.  The tall echo
area cuts off the bottom of the picture)


                       Many thanks,

                                    Whit